GeometryCollection styling in Geoserver

Question

I am trying to style an GeometryCollection geometry data type from PotGIS table in Geoserver. I have not found any examples on the Internet how to do it nor is it supported in Geoserver or not. When I try to style it using standard PolygonSymbolizer, LineSymbolizer and PointSymbolizer I get strange behaviours. For example, filled non-closed linestrings, non-exitsting points appear on linestring etc. This is one example of my SLD file and rendered WMS request.

Am I doing something wrong in my SLD?

Is GeometryCollection supported in Geoserver?

Example of SLD:

<?xml version="1.0" encoding="UTF-8"?>
<StyledLayerDescriptor version="1.0.0"
 xsi:schemaLocation="http://www.opengis.net/sld StyledLayerDescriptor.xsd"
 xmlns="http://www.opengis.net/sld"
 xmlns:ogc="http://www.opengis.net/ogc"
 xmlns:xlink="http://www.w3.org/1999/xlink"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <NamedLayer>
    <UserStyle>
      <FeatureTypeStyle>
       <Rule>
        <ogc:Filter>
         <ogc:PropertyIsEqualTo>
            <ogc:Function name="geometryType">
               <ogc:PropertyName>the_geom</ogc:PropertyName>
            </ogc:Function>
            <ogc:Literal>GeometryCollection</ogc:Literal>
         </ogc:PropertyIsEqualTo>
       </ogc:Filter>
          <PolygonSymbolizer>
            <Fill>
              <CssParameter name="fill">#FF0000</CssParameter>
            </Fill>
            <Stroke>
              <CssParameter name="stroke">#FFFFFF</CssParameter>
              <CssParameter name="stroke-width">6</CssParameter>
            </Stroke>
          </PolygonSymbolizer>
          <LineSymbolizer>
            <Stroke>
              <CssParameter name="fill">#00FF00</CssParameter>
              <CssParameter name="stroke-width">2</CssParameter>
              <CssParameter name="stroke-linejoin">round</CssParameter>
              <CssParameter name="stroke-linecap">round</CssParameter>
            </Stroke>
          </LineSymbolizer>
         <PointSymbolizer>
              <Graphic>
                <Mark>
                  <WellKnownName>circle</WellKnownName>
                  <Fill>
                    <CssParameter name="fill">#0000FF</CssParameter>
                  </Fill>
                </Mark>
              <Size>9</Size>
            </Graphic>
          </PointSymbolizer>
      </Rule>
      </FeatureTypeStyle>
    </UserStyle>
  </NamedLayer>
</StyledLayerDescriptor>

Rendered WMS request with provided SLD file:

Answer 1

What you are seeing is the correct behaviour as described by the SLD Spec. If you want to only apply one symbolizer to a feature then you need to provide a filter that selects one (or more) of the symbolizers for each feature.

The GeoServer documentation covers how to handle multiple geometries in one column quite clearly here.